Review of the current proposition
Mentions are not only for Contact (@ marker by default), it can be for any kind of objects. So your current implementation breaks it for all other classes.

If we are to go further with this ticket, then we must check if the mentioned object matches the marker it begins with.

Use case that led to this PR
When pasting text from an iTop; if the text contains the hyperlink to an object with the same meta data as the mentions, then the mention will be triggered again even if the hyperlink doesn't start with the marker (@ for Contact).

@v-dumas had this behaviour recently and thought it was nice. So there is obviously a discussion to be done, so we all decide what behaviour we want.

1. Two little typographic rules to fix
2. Having utilsTest derived from iTopDataTestCase seems overkill Is there an alternative?
3. My mistake on my previous review: multi-byte safe function has no sense when it comes to checking the very first character of a byte sequence. Moreover, a test has been added with an emoji as the "marker".

Ok for merging